Didn't really "go". There was some grinding in 3rd gear and probably just needed an oil change. But I had a cool SA who just gave me a new (rebuilt) transmission. No complaints here. If Dzennos transmission holds fine with 640+ WTQ, that is perfectly illustrative of what these beauties can take.

Didn't really "go". There was some grinding in 3rd gear and probably just needed an oil change. But I had a cool SA who just gave me a new (rebuilt) transmission. No complaints here. If Dzennos transmission holds fine with 640+ WTQ, that is perfectly illustrative of what these beauties can take.

Its the same transmission as the M5 and M6. They can take a lot. Makes me wonder if those stock clutches can be used on an n54.

my experience recently. Had RP in the car and changed to D4ATF... reason was because of RPs supposedly poor reputation for longivity (or break down easier).
The RP is much smoother, especially noticeable engaging 1st gear when stopped.
I went with D4 thinking that the higher viscosity (than D6) would have more lubricity... but I guess there really is no relationship between the 2 (lubricity and viscosity), depends on the overall formula.

my experience recently. Had RP in the car and changed to D4ATF... reason was because of RPs supposedly poor reputation for longivity (or break down easier).
The RP is much smoother, especially noticeable engaging 1st gear when stopped.
I went with D4 thinking that the higher viscosity (than D6) would have more lubricity... but I guess there really is no relationship between the 2 (lubricity and viscosity), depends on the overall formula.

Not sure if I will go back to RP or try something else.

I am on D6 and it feels the same as stock tbh. I chose d6 due to the lower drivetrain loss being less than d4. I might try RP. Which did you use specifically?

My transmission (09/2006) had an LT2 stamp so I replaced with D4. Changed fluid at 45K (planing on sending it to black stone)...No more 2nd grind. And at 10.95 a bottle (you need 2) I plan on changing every 30k. Factory fluid was something like $60 from my dealership.

Update: 2nd gear grind still occurs under the right conditions. 5k miles later I decided to switch over to D6 to see if the thinner fluid would help alleviate the issue. It's definitely an inprovement but unfortunately I can still get 2nd to grind during extremely fast and hard shifts.

At this point I recommend skipping D4, go straight to D6 and adjust your driving style around the 1-2 issue.

I am just curious as to what is causing it.. none of the other gears make even a hint of noise when slamming them aggressively, it is annoying as $#@! to say the least when you're at the strip. Am I doing any damage to my syncros by continuing to take it to the strip?

Update: 2nd gear grind still occurs under the right conditions. 5k miles later I decided to switch over to D6 to see if the thinner fluid would help alleviate the issue. It's definitely an inprovement but unfortunately I can still get 2nd to grind during extremely fast and hard shifts.

At this point I recommend skipping D4, go straight to D6 and adjust your driving style around the 1-2 issue.

sorry to bump a old thread by any updates on how the longevity d6 fluid holds up in our MTs